<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://unpkg.com/vue/dist/vue.js"></script>
</head>
<body>
<div id="app">
  <p>{{ message }} | {{ myData }}</p>
</div>

<script>
let myData = {
    a: 12
}
let app = new Vue({
  el: '#app',
  data: {
    myData,
    message: 'Vue.js'
  }
})
</script>
</body>
</html>